Stepping mechanism



June 5, 1945. H. H. SMITH STEPPING MECHANISM- Ffiled Nov. 27, 1942 2 Sheets-Sheet 1 INVENTOR. HOWARD H. SMITH ATTORNEY June 5, 1945. H. H. SMITH STEPPING MECHANISM Filed Nov. 27, 1942 2 Sheets-Sheet 2 owQE mwoc

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mnum v mac 'INVENTOR HOWARD usmm 11 ATTORNEY Patented June 5, 1945 STEPPING. MECHANISM Howard mu Smith, Chicago, n1., assignor to Attomatic Electric Laboratories, Inc.; Chicago, 11]., a corporation of Delaware Application November 27, 1942, Serial No. 467,159

I 13 Claims. My invention relates in general to an improved stepping mechanism and more specifically to a novel electromagnetically operated ratchet drive for rotating a shaft either in a forward or backward direction at will.

Devices have been designed for driving a shaft in either direction by means of a motor or by means of two separate magnetically operated ratchet drives which operate independently to rotate a shaft in either direction. In the present design a pair of electromagnetically operated ratchets are caused to jointly control a single ratchet wheel in such a manner that the direction of rotationof thewheel and its shaft is determined by the sequence of operation of the two magnets. The mechanism as shown may be manually controlled or remotely controlled from a rotating cam attached to any-rotating device.

In many instances it becomes necessary to cause a distant shaft to be controlled over electric circuits to "cause it to follow rotations of a near shaft in either direction. This becomes necessary in many arts such as remote control of radio sets, remote control of radio antenna for airplanes, and many other arts. Such a control may be utilized to cause either operation of a re mote driving element or to give a remote indication of the rotations of a driving element.

It is an object of the present invention, therefore, to provide a simple ratchet drive stepping mechanism which may be accurately controlled over an electric circuit to cause its movement in either direction.

In order to accomplish thi object I have provided the shaft' with a single ratchet wheel and a pair of ratchets operating on the same wheel. The magnets forcontrolling the two ratchets are controlled in different sequences over an electric circuit from a cam or the like to cause rotation of the ratchet driven shaft in either clockwise or counterclockwise direction dependent on the sequence of operation of the two magnets.

In the drawings Fig. 1 is a front view of the stepping mechanism;

Fig. 2 is a view taken from the-right side of Fig. 3 is a top view of Fig. 2 with the complete plate shown, the point at which the side plate of Fig. 3 has been broken away in Fig. 2 isindicated by line 2-2 in Fig. 3;

Fig. 4 is a circuit showing the control of the operating magnets by a cam with the mechanism shown in schematic form.

successive steps of the ratchet wheel and shaft in one sequence of operation of the magnets to move the wheel clockwise. I

Figs. 6, 6A, 6B and 6C are views showing the successive steps of the ratchet wheel in another sequence of operation of the magnets to move the wheel counterclockwise.

Referring now to Figs. 1, 2 and 3, it will be seen that the mechanism comprises a U-shaped mounting bracket i which supports the entire mechanism. 'At the open end of bracket I is mounted another smaller U-shaped bracket 2 which is secured to bracket I by screws on each side as shown in Fig. 3, and to which the magnets i and i are secured as shown. The armatures h and 8 of magnets 3 and 6 respectively are pivoted as shown on the 'pins 1 and t which project through the opposite sides of bracket i and are riveted on their ends to hold them in. place.

AQdouble-toothed pawl 9 is secured as shown to the armature 5 by means of screws shown in Fig. 2 and a similar pawl m is secured to armature t as shown. Each of the pawls t and ill have opposed teeth 9a and 9b, and Mia and it!) on opposite sides of the star ratchet wheel ii. The star wheel Iii has a hub MD on one side thereof by means of which it is rigidly secured by a set screw (Fig. 3) to a shaft i2. The shaft it has hearings in the side plates of bracket 5 and carries at one end the reset thumb nut It also rigid with the shaft. The opposite end of shaft i2 is shown as linked to the operating shaft of a so-called Veeder counter indicated generally at M which is mounted as shown in Fig. 3 on a side bracket it which is in turn secured to the side plate of bracket i. A pair of lugs i6 and ii are cut out from and bent inward from the sides of bracket 1 and have holes therein so that Fig. 1 with the side plate broken away; i

each acts as an anchor for one end of retracting springs it and iii the other ends of which are fastened to small lugs on pawls 9 and Iii to hold said pawls in normally retracted position as shown in Fig. 2. -In addition adjustable back stops 20 and 2! are shown secured by screws to the front end of bracket 1 and may be bent forward or backwardto adjust the stroke of the armatures 8 and i0. As shown in Fig. 1 the front end 'of U- shaped bracket i has a cut out section in the center thereof and has threaded holes in the two g straps on each side of the opening by means of which th wholeunit may be fastened to any desired support. It will be noted that the star wheel H is more than twice as thick as the two pawls 9 and I0 and that the pawls are arranged springs l8 and J8 (Fig. 2).

side by side, both in operative relation with the star wheel ll.

Referring now to Fig. 4, I have shown one form of circuit by means for which the magnets 3 and 4 may be operated in different sequences to rotate star wheel II and consequently shaft l2 in either clockwise or counterclockwise direction. At 22 I have shown a cam of insulating material which may be either rotated by hand or secured to a rotatable shaft of any desired form. The cam 22 has two cam faces 23 and 2,4 which function as the cam is rotated to raise and lower the main springs 25 and 26 into and out of engagement with the springs 21 and 28.

When the cam 22 is rotated clockwise the springs 26 and 28 are first closed by cam face 22 to energize magnet 3, then while these springs remain closed the springs 25 and 21 are closed by cam face 23 to energize magnet 4. As the cam 22 rotates further the springs 26 and 28 are first opened to deenergize magnet 3 and later the springs 25 and 21 are opened to deenergize magnet 4. This results in a clockwise movement of wheel H and shaft l2 one tenth of one revolution as will be more fully explained.

Now when cam 22 is rotated counterclockwise springs 25 and 21 are first closed to energize magnet 4, then springs 26 and 28 are closed to energize magnet 3, then springs 25 and 21 are opened to deenergize magnet 4 and springs 26 and 28 are later opened to deenergize magnet 3. This latter cycle causes rotation of wheel II and shaft l2 one tenth of a revolution counterclockwise.

In order to clearly explain the different directions of movement of wheel ll under the above two conditions, I haveshown in Figs. 5, 5A, 5B, and 5C the steps of operation of wheel II when cam 22 is rotated clockwise. Fig. 5 shows all parts at normal with teeth 8a and llla of the pawls in position to engage the upper sides of teeth lla and llb and with teeth 9b and "lb both held tightly against the sides of the teeth of wheel H as shown by means of the tension of On the first step; namely, when.springs'26 and 28 close and mag-' net 3 energizes, the armature 5 is attracted to move pawl 9, which as shown in Fig. 5A engages the upper side of tooth ll a to rotate the wheel to the position shown with tooth lie of wheel ll engaging the upper edge of the tooth lllb of pawl It. On the next operation, as pointed out,

the springs 25 and 21 (Fig. 4) cause energization of magnet 4 and consequent attraction of armature 6 to move pawl It! to the position shown in Fig. 5B. This movement draws the tooth lflb downward slightly at the same time that tooth Illa engages, in this case, the under side of tooth lib of wheel II and thereby causes a still farther rotation (clockwise) of wheel II and permits tooth 3a to also move completely into the tooth of wheel II as shown. The next step in this sequenceof operations occurs when springs 26 and 28 are opened (Fig. 4) to cause deenergization of magnet 3, and consequent retraction of its armature 3, by its spring l8 to theposition shown in Fig. 50. As pawl 3 moves to this position pawl tooth 31) engages the under side of tooth lie, pawl tooth 3a moves out-of the teeth of wheel H, and as magnet 4 is still energized, the

wheel ll rotates a still further amount clockwise so that tooth Illa now fully enters its engaged tooth of wheel H as shown in Fig. 5C. At the next step in this sequence cam 22 (Fig. 4) opens springs 21 and 23 to cause deenergization of magnet 4 to allow retraction of pawl II by its spring I9.

As pawl I8 is retracted the tooth lllb of pawl l8 engages the right hand side of tooth No as seen in Fig. 5C and tooth Illa is withdrawn from the teeth of wheel ll so that the wheel is moved still farther clockwise. The pawls 8 and I8 will now again assume the positions shown in Fig. 5 except that wheel II has now completed one sequence of operations and moved one tenth of a revolution with tooth II a in the position shown by tooth He in Fig. 5. It willbe noticed that this sequence of operations of magnets 3 and 4 for clockwise rotation started with-the energy of magnet 3.

Now if cam 22 (Fig.4) is moved counterclockwise a similar sequence occurs except that magnet 4 is first energized and the steps in this sequence of operations are shown in Figs. 6, 6A, 6B and 60. Fig. 6 again shows normal positions of pawls 9 and I8 so that when cam 22 closes springs 25 and 21 and energizes magnet 4 the pawl l0 moves first to engage the upper edge of tooth l lb to move wheel II to the position shown in Fig. 6A with the lower side .of tooth I Id against the upper edgeof pawl tooth 9?). On the next step when springs 26 and 28 close and magnet 3 energizes the pawl 9 moves forward to the position shownin Fig. 63 to cause tooth 9a to engage the under side of tooth Ilaand to withdraw tooth 912 from under tooth lld so that wheel ll moves counterclockwise and tooth Illa now completely fills the tooth opening which it engages. Cam 22 (Fig.- 4) now enters its next stage to open springs 25 and 21 to deenergize magnet 4 to permit retraction of pawl In by its power spring III. This movement withdraws tooth Illa from the wheel and causes tooth ll'lbto engage the under side of tooth II to rotate wheel ll still further counterclockwise with tooth 9a now completelyfilling its engaged tooth as shown in Fig. 6C. The next step, namely, the opening of springs 26 and 28 and consequent deenergization of magnet 3 causes pawl 9 to be moved to the right about its pivot from the position shown in Fig. so that tooth 9b engages the under side of tooth lld as tooth 9a is withdrawn from wheel H to cause further counterclockwise movement of wheel II to the position shown by the pawls in Fig. 6 except that one tenth revolution has been completed and tooth I I0 now stands in the position shown in Fig.

6 by tooth Ila.

It will be seen that further rotation of cam 22 (Fig. 4) causes like rotations of wheel II in the same manner. That wheel ll always has a direction of movement in the same direction as cam 22 and that as shown one revolution of cam 22 causes one tenth of one revolution of shaft l2.

It will be further understood that many adaptations of this arrangement are possible and that various gear ratios may be introduced as desired. For instance the shaft l2 instead of operating a visual indicator or counter, as shown, may be geared or directly connected to the tuning elements of a radio or to means for reeling in or out a radio antenna of an airplane and that in this case cam 22 would be manually controlled from the tuning dials of the radio or from other manual control means. Also the cam 22 may be geared 'to or connected to a remote operating shaft of any device and be utilized to control any ype of rotary visual dial or indicator at the near point by means of magnets 3 and 4 to give a continuous indication of the position of the remote device.

Having fully described the features and operation of the mechanisms.

pawls.

operation to move the wheel, each tion of eachpawl causing of the wheel in one direction.

aspects of my invention, what I consider to be new and'novel and desire to protect by Letters Patent will be pointed out in the appended claims.

I claim: r 1. In a stepping mechanism, a,shaft, a pair of 'electromagnetically operated ratchet mechanisms for rotating said shaft, means for alternately operating said ratchet mechanisms, said mechanisms so adjusted that the alternate operation thereof causes rotation of the shaftin one direction, the direction in which the shaft is rotated being determined by the sequence of 2. In a rotating mechanism, a rotatableeiement, a series of ratchet teeth on the element, a pair of pawls cooperating with said teeth,

means for operating said pawls alternately in different sequences, said pawls so aligned with said teeth that each alternate operation of the pawls causes rotation of the element in one dimotion, the direction of rotation of said element determined by the sequence of operation of the 3. In a stepping mechanism, a ratchetwheel, a pair of pawls, means for operating said pawls electromagnets, a pawl operated by each magnet and a ratchet wheel controlled by both pawls,

- means for causing overlapping energization and deenergizati'on of said magnets to progressively move the wheel in one direction, said pawls so aligned with said wheel that the direction of movement of the wheel is determined by which magnet is first energized.

8. In a ratchet drive mechanism, a ratchet wheel,- a pair of pawls engaging the teeth of 5 said wheel to rotate the same, a-magnet for operating each pawl, means foralternately energizing and deenergizing said magnets to cause; both pawls to cooperate to rotate said wheel in one direction, each pawl so positioned relative to the teeth of said wheel that each energization and each -deenergization of each magnet causes its pawl to partially rotate said wheel.

9. A ratchet drive mechanism as claimed in claim 8 wherein the direction of rotation of said wheel is determined by the initial energization of a diiferent one of said magnets.

10. In a ratchet drive mechanism, a star wheel,

4/ a pair of double toothed pawls cooperating with toengage the teeth of said wheel to rotate the same, said pawls so mounted relative said wheel that the wheel is moved in one direction by initial tion by initial operation of said pther pawl and subsequent operation of said one pawl.

of one pawl and subsequent operation, of the other pawl, andmoved in the other direc- 4. In a stepping mechanism wherein a pair of pawls engage the teeth of a single ratchet wheel, means for operating the pawls in one order, and

for operating said pawls in the reverse order,-

said pawls so mounted relative to the wheel that the operation thereof in one order is effective to move the wheel in one direction and the operation ofthe pawls in the reverse order is effective to move the wheel in another direction.

5. In a stepping mechanism a ratchet-wheel and a pair 'of pawls therefor, means for. alternately operating said pawls to cause rotation of the wheel, said pawls so aligned with the teeth of said wheel that operation of one pawl before' of operating magnets, pawls operated by each magnet for stepping said shaft, means for energizing said magnets in different sequences to cause stepping of the shaft, said pawls so posi- 40 tioned that the direction of movement of the the other causes rotation of the wheel in one direction while'operation of said one pawl after the initial operation of the other pawl causes rotation of the wheel in the other direction.

6. In a stepping mechanism, a ratchet .wheel,

a pair of pawls each having .a pair of teeth alternately cooperating with the teeth of the wheel,

means for operating the pawls one after the pawl with .said wheel attraction and retracprogressive movement 7. In a ratchet driven mechanism, a pair of .55 other to first cause engagement of one tooth and then" the other of each shaft by each pawl is determined by the sequence of operation of the magnets, and that each energization of a magnet and each deenergization thereof causes .a movement of said shaft by its pawl.

1 2. In a stepping mechanism, a star wheel, a pair of pawls cooperating therewith, a pair of opposed ratchet teethfor each pawl, means for attracting and retracting said pawls, each attraction of a pawl causing movement of the wheel by means of one tooth of the pawl, each retraction of a pawl also causing movement of the wheel by means of the other tooth thereof.

13. A stepping movement such as claimed in claim 12 wherein the said pawls cooperate to control the wheel to step the same in either direction, and wherein the direction of movement of the wheel is determined by which pawl is initially attracted. v

I-IQWARD B. SMITH. 

